Development of Green Engineered Cementitious Composites

2014 ◽  
Vol 1020 ◽  
pp. 3-8 ◽  
Author(s):  
Marek Jašek ◽  
Jiri Brozovsky ◽  
Lucie Mynarzová ◽  
Jan Hurta

A development of fiber-cement composites is often focused on cost-effective and environmentally friendly materials (so-called green materials). Production of this material should produce less waste and it also should use less energy and less natural sources. There are numerous approaches to the development of green composites. One of the possible ways is a utilization of fly ashes instead of the cement part of composite. The paper discusses a development of green cementitious composite which incorporated fly ash materials produced in the Moravian-Silesian region as a partial replacement of the cement part of the composite.

2018 ◽  
Vol 761 ◽  
pp. 73-78 ◽  
Author(s):  
Matej Špak ◽  
Pavel Raschman

Alkali-activated materials based on fly ash are widely developed and also produced on the present. Some of fly ashes are not suitable for production of alkali-activated materials because of their inconvenient chemical composition. Alumina-silicates are the most important components that are needed to accomplish the successful reaction. The proper content of amorphous phase of alumina-silicates and its proportion as well should be provided for the final composition of alkali-activated materials. The influence of pure aluminum oxide powder as well as raw milled natural perlite on mechanical properties and durability of alkali-activated mortars was investigated. These minerals were used as partial replacement of fly ash coming from black coal combustion. In addition, the mortars were prepared by using different alkali activators.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2607 ◽  
Author(s):  
Chenhua Jin ◽  
Chang Wu ◽  
Chengcheng Feng ◽  
Qingfang Zhang ◽  
Ziheng Shangguan ◽  
...  

Strain-hardening cementitious composite (SHCC) is a kind of construction material that exhibits multiple cracking and strain-hardening behaviors. The partial replacement of cement with fly ash is beneficial to the formation of the tensile strain-hardening property of SHCC, the increase of environmental greenness, and the decrease of hydration heat, as well as the material cost. This study aimed to develop a sustainable construction material using a high dosage of fly ash (no less than 70% of the binder material by weight). Based on the micromechanics analysis and particle size distribution (PSD) optimization, six mixes with different fly ash to cement ratios (2.4–4.4) were designed. The mechanical properties of the developed high-volume fly ash SHCCs (HVFA-SHCCs) were investigated through tensile tests, compressive tests, and flexural tests. Test results showed that all specimens exhibited multiple cracking and strain-hardening behaviors under tension or bending, and the compressive strength of the designed mixes exceeded 30MPa at 28 days, which is suitable for structural applications. Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this study is suggested for structural applications.


2020 ◽  
Vol 47 (12) ◽  
pp. 1311-1319 ◽  
Author(s):  
Adeyemi Adesina ◽  
Sreekanta Das

Engineered cementitious composite (ECC) is conventionally made up of high content fly ash (FA) combined with Portland cement (PC) as a binder. However, the growing call for sustainability is leading to continuous decommissioning of various coal power plants around the world thereby limiting the supply of fly ash available for ECC production. Therefore, it is of high importance to find alternative materials that can be incorporated into ECC as a partial replacement of the conventional binders. This experimental investigation was carried out to investigate the feasibility of incorporating glass powder (GP) as binder into ECC mixtures. The mechanical performance in terms of its compressive, tensile, and flexural properties was evaluated. Results from this study showed that 25% FA can be replaced with GP without any significant reduction in the mechanical performance of ECC mixtures. Microstructural investigations of the mixtures incorporating GP show good bonding between the cementitious matrix and the fibres.


Buildings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 225 ◽  
Author(s):  
Agnieszka Michalik ◽  
Joanna Babińska ◽  
Filip Chyliński ◽  
Artur Piekarczuk

The paper presents the results of research on the properties of fly ashes from the process of flue gas denitrification by selective non-catalytic reduction (SNCR), consisting of dosing urea into the coal combustion chamber. The research was carried out on two types of fly ash: Silica fly ash from flue gas denitrification and ash from a traditional boiler without the flue gas denitrification process. The scope of comparative studies included physicochemical and structural features of ashes, as well as slurries and mortars with the addition of ashes. Fly ash from denitrification, whose ammonia content at the time of sampling was 75 mg/kg at the maximum, was examined. Our own research has shown that fly ash from flue gas denitrification is characterized by a higher value of losses on ignition and ammonia content in comparison to ashes without denitrification. It was shown that the ammonia content in the analyzed range does not limit the use of fly ash as an additive to cement and concrete.


2021 ◽  
Author(s):  
Maulin Bipinchandra Mavani

Engineered Cementitious Composite (ECC) is an ultra ductile concrete with strain-hardening and multiple-cracking behaviour in tension and flexure. Fresh, mechanical and durability properties of different ECC mixtures are evaluated by incorporating supplementary cementitious materials (class F, CI fly ash and slag) and different aggregate type. Experimental studies demonstrated viability of producing greener, sustainable and cost-effective ECC using locally available aggregates (crushed sand) instead of microsilica sand and fly ash (Class CI or F) of up to 70% cement replacement having similar or better fresh, mechanical and durability properties. Structural validation by small scale tests on bridge decks with ECC link slab and by push out tests to evaluate stud shear connector-ECC interaction compared with self-consolidating concrete (SCC) proved feasibility and advantages of these ECC mixes. Based on research, recommendations are made for ECC mix design and their application in link slab construction in bridge structures.


Buildings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 67 ◽  
Author(s):  
Jolanta Harasymiuk ◽  
Andrzej Rudziński

The use of industrial residues to replace natural resources for the production of building materials is economically and ecologically justified. Fly ash (FA) taken directly from electro-filters is commonly used as a cement replacement material. This is not the case, however, for old dumped fly ash (ODFA) that has been accumulating in on-site waste dumps for decades and currently has no practical use. It causes environmental degradation, which is not fully controlled by the governments of developed countries. The aim of the study was to assess the possibility of using ODFA as a partial replacement for sand in cement composites. ODFA replaced part of the sand mass (20% and 30%) in composites with a limited amount of cement (a cement-saving measure) and sand (saving non-renewable raw material resources). ODFA was activated by the addition of different proportions of hydrated lime, the purposes of which was to trigger a pozzolanic reaction in ODFA. The quantitative composition of the samples was chosen in such a way as to ensure the maximum durability and longevity of composites with a limited amount of cement. The 28-day samples were exposed to seawater attack for 120 days. After this period, the compressive strength of each sample series was determined. The results suggest the possibility of using ODFA with hydrated lime to lay town district road foundations and bike paths of 3.5 to 5 MPA compressive strength. What is more, these composites can be used in very aggressive environments.


2009 ◽  
Vol 6 (1) ◽  
pp. 231-236 ◽  
Author(s):  
G. Sivakumar ◽  
K. Mohanraj ◽  
S. Barathan

In this paper, the hydration behaviour of ordinary portland cement (OPC) and fly ash blended cement (10, 25 and 40%) replaced by two different fly ashes (FA) were investigated. The samples were hydrated with distilled water (DW) in water to solid ratio 0:4 and its setting time and dielectric measurement are carried out. Results of the study found that the fly ash blended cement composites have slow hydration than OPC during early stages (up to 24 h).


2018 ◽  
Vol 48 (2) ◽  
pp. 20170596
Author(s):  
Jing Ji ◽  
Shilong Zhang ◽  
Liangqin Jiang ◽  
Lijian Zhou ◽  
Zhichao Xu ◽  
...  

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Erwin Rommel ◽  
Dini Kurniawati ◽  
Arman Putra Pradibta

PERBAIKAN SIFAT FISIK DAN REAKTIFITAS FLY ASHSEBAGAI CEMENTITIOUS PADA BETON Improvement of  The Physical Properties and Reactivity of Fly Ash As Cementitious On ConcreteErwin Rommel1, Dini Kurniawati2, Arman Putra Pradibta31,2,3Jurusan Teknik Sipil Fakultas Teknik – Universitas Muhammadiyah MalangAlamat korespondensi : Jalan Raya Tlogomas 246 Malang 65144email : [email protected] of materials researchs is curently underway to develop environmentally friendly concrete is very varied in order to meet the demands of higher cement production. One way is to replace some of the cement with the rest of coal burning PLTU or commonly known as fly ash. Purpose of this study was to determine the effort to improve the physical and chemical properties of fly ash as a partial cement replacement material and influence the reactivity of fly ash has improved by incubating the silica synthesis. The physical examination, fly ash decreased in term of quality and fineness increase in the adsorption of the water content. The chemical test showed that a decline in the percentage of the elements Si and Al but an increase in elemental Fe. It also affects the content of the main compound SiO2 and Mullite are dominated by 77 – 80% fly ash decreased after a treatment process. Reactivity test using XRD found that fly ash has decreased the amount of 3,47% amorphous structure after experiencing the treatment. Fly ash that would be dominated by the reactive silica is a form of amorphous silica, is because the contact surface af amorphous silica is greater than crystalline. This reduction causes no more reactive fly ash after going through the process of treatment and no better used as a partial replacement for cement in concrete. Keyword : fly ash, environmentally friendly concrete, and synthesisAbstrakTeknologi bahan dan teknik untuk mengembangkan beton ramah lingkungan sangat bervariatif guna menjawab tuntutan produksi semen yang semakin tinggi. Salah satu caranya ialah mengganti sebagian semen dengan sisa pembakaran batubara dari PLTU atau yang biasa disebut fly ash. Tujuan dari penelitian ini adalah untuk mengetahui upaya memperbaiki sifat fisik dan kimia dari fly ash sebagai material pengganti sebagian semen serta pengaruh reaktifitas dari fly ash yang telah mengalami perbaikan dengan pensintesisan silika. Hasil pemeriksaan fisik, fly ash mengalami penurunan dalam segi kualitas kehalusan dan mengalami kenaikan dalam penyerapan kadar air setelah mengalami proses treatment.Hasil pemeriksaan kimia menunjukkan bahwa terjadi penurunan persentase pada unsur Si dan Al akan tetapi mengalami peningkatan pada unsur Fe. Hal tersebut juga berpengaruh terhadap kandungan senyawa utama SiO2 dan Al6Si2O13 (Mullite) yang mendominasi fly ash sebesar 77 – 80 % mengalami penurunan setelah mengalami proses treatment. Hasil uji reaktifitas dengan menggunakan XRD didapatkan bahwa fly ash mengalami penurunan jumlah struktur amorf sebesar 3,47 % setelah mengalami proses treatment. Penurunan ini menyebabkan fly ash tidak lebih reaktif setelah melalui proses treatment dan tidak lebih baik digunakan sebagai bahan pengganti sebagian semen dalam beton secara keseluruhan.Kata Kunci :  fly-ash, beton ramah lingkungan,  sintesis


1989 ◽  
Vol 178 ◽  
Author(s):  
Kenneth L. Bergeson ◽  
Carol L Kilgour ◽  
Douglas Overmohle

AbstractInability of the Iowa fly ash industry to meet their demands for fly ash during the peak construction months led the Iowa Fly Ash Affiliates to initiate research into storage alternatives for high-calcium fly ashes. Conventional, closed storage facilities are extremely expensive and currently not cost effective. In addition, the industry is faced with the rising costs of landfill disposal. This paper presents the results of utilizing the rapid self-cementitious properties of high-calcium ashes to agglomerate them into discrete, aggregate size particles for stockpiling. The two fly ashes used in this study contained 25 to 30 percent calcium. Water was used as an agglomerating medium. Agglomeration was accomplished using three types of commercial equipment as follows: continuous rotary pan agglomerator, continuous auger agglomerator and a batch turbine agglomerator. All units produced relatively well graded aggregate material differing primarily in particle shape and texture. Research work discussed includes gradation, strength, and durability of the agglomerates. Agglomerates were also reground using a newlydeveloped, energy efficient, micronizing technique. Research results using the reground ash in concrete and soil stabilization are presented.


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